Expansible mandrel



Sept. 18,` 1934.

F. GRAFFEN'BERG'R EXPANSIBLE MANDREL Filed Feb. 16. 1935 (Ittomeg Patented Sept. 18, 1934 UNITED STATES PATE-NT OFFICE 6 Claims.

This invention relates to expansible mandrels for paper rolls and the like. ,v

With the equipment heretofore employed, hollow cores of cardboard or the like have constigtuted essential elements in the winding' of paper rolls. InV methods commonlypracticed, the core forms an appropriate ,base or foundation to which the paper is glued and thus readily fixed with sufficient security to sustain the load imposed by the 10 Vordinary tension in the paper web during winding or unwinding of the roll. The core is ordinarily gripped at its ends by inserts of one form or another, which frequently damage the core, and sometimes the roll, and which are commonly unable to effect a grip upon the core sufficiently secure to prevent slippage.

Many core substitutes have been proposed, heretofore, but, for one reason or another, none have approacheda degree of success to warrant -their adoption, and all have been. discarded;

An object of the present invention is; to provide a mandrel to which the paper or like web to be wound may be directly applied and securely attached without necessitating the use of a core. This I have accomplished by the provision of `a mandrel, radially expansible uniformly from end to end, and having a paper gripping external surface which, by expansion, may be forcibly pressed into binding contact with that end portion of the paper web which has been looped and wrapped about it preliminary to a winding operation. r`The external surface of the mandrel is preferably longitudinally ribbed or otherwise fashioned to increase the grip upon the paper.

Another object is to provide an expansible mandrel which may be readily adjustable lengthwise into position to assure proper tracking of the paper web during winding or unwinding of the paper roll. 1 Another object is to provide, in an expansible mandrel of the character mentioned, means which will assure expansion thereof to cylindrical shape of uniform diameter at both ends. This feature is of marked utility when the mandrel employed for winding.

Another object' is to provide an expansible mandrel which isdurable and which is not susceptible to damage by wearing of its parts in normal use. This I accomplish by the use of an expansible tube and axially adjustable tapered plugs having tapered faces which seat accurately within complementary sockets in the endsof the tube, so as to afford extended bearing areas therebetween at all positions of adjustment of the plugs within the sockets. Y

Figure lis a View in elevation of an expansible mandrel constructedfin accordance with the present invention. Y

Fig. 2 is a longitudinal sectional view thereof;

Fig. 3.is a transverse sectional view on the line 3--3ofFig.11. C L x Fig. 4 is a' sectionalf'view on the'line 4 4v of Fig. 1. Y

Fig. 5 is a fragmentary section on the line 5--5 of Fig. 3.

The mandrel l selected for villustration Vcomprises a radially expansibl'e tube l, mounted upon a pair of inwardly tapered end plugs 2slidably engaged therein and axially bored'to slidably receive a conventional shaft 3. The plugs 2 are adjustably fixed to the shaft by appropriate means such as set screws 4, which, when released, will permit axial adjustment ofthe plugs inwardly or outwardly of the tube-tok expand or contractrthe same, and also permit longitudinal adjustment of the plugs and tube, as a unit, along the shaft to center the same with respect to the paper web and thereby assure proper trackingV of the web. l

It will be noted that, in the spindle shown, each tapered Aexpansion plug 2 is provided with a plurality of plane faces 8 arranged to define a truncated pyramid, and that the inner ends of the expansible tube lare correspondingly provided with' similarlplane internal faces Saforming Ysockets complementary to the pyramidal expansion plugs. Due to this arrangement, each plug'face 8 contacts with the coacting socket face 9 over an extended area, in all adjusted positions of the plugs, so as to maintain extended bearing areaswell able to sustain the heavy loads to which they 'are subjected Without material wear.'`

The expansible tube l is made of steel or other suitable resilient material and is designed for uniform radial expansion by being provided with longitudinal slits l0 and 1l which extend alternately from each end toa point near the other, endin overlappingu relation, thus dividing the tube into resilient segments 12. Each of the segments VV12 is joined at one end to an adjacent segment by an .integral end segment -13`, and at to further expand the tube against the paper.

its other end to the adjacent segment at the other side thereof by a similar end segment.

In order that the pyramidal expansion plugs 2 may function to separate the segments and expand the tube, the longitudinal slits are spaced as shown in Fig. 3 to permit alternate angles on each expansion plug to enter the slits between the end segments 13. In this manner, each end segment 13 is provided with two faces 9 which meet at the middle of the segment and engage two complementary faces 8 on the plug 3, so that each end segment 13 may move relative to the other end segments as the expansion plug is moved into or withdrawn from the socket in the end of the expansible tube. As the end segments 13 move in substantially radial direction relative to the axis of the spindle, it is apparent that the internal faces 9 in the segments remain in engagement with the external faces 8 on the expansion plugs in all positions of the plugs within the sockets.

Preparatory to winding, the paper to be wound may be securely fastened to the tube 1 by passing an end thereof through alternate slots ll or. 12 of the tube, as indicated yat 5 in Fig. 4, folding it back and gluing it upon itself, wrapping it about the tube to form an encompassing coil, and finally, by adjustment of the tapered plugs 2, expanding the tube so as to forcibly press the external surface thereof against the paper of the coil thus formed. To improve the grip, the tube.

is preferably longitudinally corrugated to provide a sharply ribbed external surface 1. After the winding operation, one or both .of the plugs 2 may be withdrawn, to contract the tube l, and the tube removed lengthwise from the finished roll, lthe looped end 5 of the-paper passing freely through the open ends of the slots through which it had previously been threaded.

It has been found that, with the ribbed formation 1', a grip between the mandrel and paper,

suiiiciently secure for some purposes, may be effected by merely looping the end of the paper about the tube, rather than through the slots 11 or l2, gluing the same upon itself, Wrapping it about the tube, and finally expanding the tube against the encompassing paper coil thus formed. During winding, the mandrel may be'drivenby power applied, in a well known manner, to the shaft 3, and during that operation the polygonal or pyramidal formation of the plugs 2 and mating end sockets in the tube 1 provide an effective torque transmitting connection between the shaft and tube, and the resulting cam action Abetween the faces 8 and 9 of the plugs and sockets tends wound thereon. 'Ihe plugs and socketsfcoact in a similar manner when, during unwinding, an artificial resistance is applied to the shaft'3, to maintain the desired tension in the paper web as it is drawn from the roll.

When an unusually Wide web of paper isY to be wound, requiring a rather long mandrel, the mandrel is preferably reinforced at its ends byl appropriate collars 15, seated upon reduced end portions of the tube 1. These collars serve to preserve the circular contour of the tube and also to increase the grip between the plugs.2 and their mating end sockets.

The mandrel shown may also be employed to advantage in carrying out that type of winding process wherein the mandrel, and its roll, rest upon and between a pair of parallel driving rollers '7,as indicated in Fig. 4; When Vso employed, the collars 1:5 are preferably of a size to project beopposite ends of the tube.

yond the surface of the tube 1, so as to bear against the rollers '7 and thus space thc tube 1 therefrom at the start of the winding operation. It has been found that there is less likelihood of tearing the paper web, in starting, with the end collars l5 arranged in the manner described.

The collars 15 also serve to limit the expansion of the tube 1 and to thus assure that the tube is of uniform diameter throughout and particularly of the same diameter at both ends, This condition is necessary, in winding, in order that the paper may run true, and form a perfect roll.

rAs a precautionary measure, or as an alternative, the tube 1 may be equipped with stop-pins 16 which also assure a uniformity of diameter of the In this instance, each of the plugs 2 is provided with a transverse hole 17, the opposite ends of which are slightly flared to form tapered pin receiving seats. Ordinarily only one pin is inserted in one of the seats in each plug 2, the other seat being reserved for use in the event of accident, wear, or damage to that seat being used. The projecting end of each pin 16 is preferably partially removed to form a shoulder 18 which affords a good bearing area for engagement with the end of the tube. The pins 16 accurately limit .the inward adjustment of the plugs 2 into the tube l and thus accurately determine the degree of expansion and ultimate diameter of each end of .the tube.

-The mandrel hereinabove described has been successfully employed in the winding and unwindingof paper rolls without the use of the core heretofore required. It has alsobeen used with a core. '.When a core is used, the mandrel shown may be readily expanded into secure gripping contact with the interior wall of the core, and may as readily be contracted and withdrawn from the core. When used with a core, the collars l5 and stop-pins 16 are unnecessary.

Various changes may be made in the embodiment ofthe invention hereinabove described without departing from or sacrificing the advantages of the invention as defined in the appended claims.

-I claimr- 1. An expansible mandrel for rolls vof paper or the like comprising two coaxially arranged inwardly tapered plugs, each plug having a plurality of plane faces defining a truncated pyramid, a radially expansible tube having inwardly tapered sockets' in its Vopposite ends in which said plugs are slidably engaged and adjustable to expand said tube, each of said sockets having faces complementary to those of its mating pyramidal plug, said tube having slits extending alternately from opposite ends thereof to a point adjacent the other end to Yrender said tube uniformly expansible throughout its length, said slits at each end being radially aligned with alternate angles on said plugs, and means for releasably xing said plugs relative to said tube. n

2.15111 expansible mandrel comprising two coaxial inwardly tapered plugs each provided at its inner end with faces defining a truncated pyramid, angexpansible tube carried by saidr plugs having in each end a socket with faces complementary to the faces on said plugs and being slit alternately from'opposite ends to a position near the other end, said slits at each end being radially aligned with alternate angles on said plugs whereby the-tube may be expanded by moving said plugs axially intosaid sockets with said complementary faces in engagement, a ring encircling each end 0f said tube to clamp it upon said plug, and means lll-5 for releasably fixing said plugs relative to said tube.

3. An expansible mandrel for rolls of paper or the like comprising a radially expansiole tubular structure having longitudinal slots dividing the ends of said structure into separable segments, each end segment having a pair of internal faces inclined relative to each other and to the longitudinal axis of the structure, and tapered end plugs having external bearing faces complementary to said internal faces of said segments and coacting therewith to support said structure and to regulate the expansion thereof.

4.. An expansible mandrel for rolls of paper o1' the like comprising a one piece tube longitudinally slotted to render the same radially expansible, each end of said tube comprising separable segments, each of said segments having a pair of internal faces inclined relative to each other and to the longitudinal axis of said tube, and tapered end plugs having external bearing faces complementary to said internal faces of said segments and coacting therewith to support said tube and to regulate the expansion thereof.

5. An expansible mandrel for rolls of paper or the like comprising a one piece radially expansible tube, V-shaped longitudinal ribs formed on the exterior thereof, each end of said tube having separable segments, each of said segments having a plurality of internal faces inclined relative to each other and to the longitudinal axis of said tube, and'adjustable end plugs having external faces complementary to Vsaid internal faces of said segments and coacting therewith to expand said tube.

6. An expansible mandrel for rolls of paper and the like comprising a tubular structure radially expe-risible substantially uniformly throughout its length, said structure having external V-shaped ribs extending longitudinally thereof, and means for expanding said structure to force the edges of said ribs into biting engagement with a roll thereon.

FRIEDRICK GRAFFENBERGER. 

